WO2019019582A1

WO2019019582A1 - Optical film, backlight module and display apparatus

Info

Publication number: WO2019019582A1
Application number: PCT/CN2018/074342
Authority: WO
Inventors: 李晓虎; 孙含嫣; 朴仁镐
Original assignee: 京东方科技集团股份有限公司; 北京京东方显示技术有限公司
Priority date: 2017-07-28
Filing date: 2018-01-26
Publication date: 2019-01-31
Also published as: US11300829B2; US20200348565A1; CN107422528A

Abstract

An optical film (11, 111, 112), a backlight module and a display apparatus. At least some positions (A, A1, A2) on the surface of the optical film (11, 111, 112) are coated with a transparent photochromic material. The backlight module comprises a light source (131), a light guide plate and the optical film (11, 111, 112). The display apparatus comprises the backlight module.

Description

Optical film, backlight module and display device

Cross-reference to related applications

The present application claims priority to Chinese Patent Application No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei.

Technical field

The present disclosure relates to an optical film, a backlight module, and a display device.

Background technique

In the liquid crystal display, the number of LEDs (Light Emitting Diodes) used on the backlight module is small, and the distance between the LED light emitting surface and the effective display area of the display panel and the distance between the LED particles on the light bar is unreasonable. The large amount of light plate activity and the unreasonable design of the light guide plate's Internet point will have obvious phenomenon of uneven brightness and darkness on the side of the backlight module near the LED, which is called the Hotspot phenomenon, so that the brightness of the light emitted by the backlight module is not Evenly.

At present, a V-shaped groove (V-Cut) is generally formed on the light-incident side of the light guide plate, and the brightness uniformity of the light emitted by the backlight module is improved by the V-shaped groove structure.

Summary of the invention

The present disclosure discloses an optical film having at least a portion of its surface coated with a transparent photochromic material.

Alternatively, when a portion of the surface of the optical film is coated with a transparent photochromic material, the photochromic material has a coating width of 10 mm to 20 mm.

Optionally, the photochromic material has a coating thickness of less than 200 [mu]m.

Optionally, the photochromic material comprises an organic photochromic material.

Optionally, the organic photochromic material comprises spiropyrans, chlorpyrifos, diarylethenes, azobenzenes.

Optionally, the photochromic material comprises an inorganic photochromic material.

Optionally, the inorganic photochromic material comprises a transition metal oxide, a metal halide, a rare earth complex.

Optionally, the photochromic material comprises a transparent resin mixed with a photochromic pigment.

The present disclosure also discloses a backlight module including a light source, a light guide plate and the above optical film.

Optionally, the photochromic material is coated at a position close to the light source of the backlight module to form a occlusion of the bright spot when a bright spot appears on a light guide plate of the backlight module near the light source.

Optionally, the optical film comprises one or more of a diffusion sheet, a prism sheet, and a reflection sheet.

Optionally, the light source is an LED light source.

The present disclosure also discloses a display device including the above backlight module.

DRAWINGS

1 shows a schematic structural view of an optical film of some embodiments of the present disclosure;

2 is a schematic structural view of a backlight module coated with a photochromic material on a surface of a diffusion sheet according to some embodiments of the present disclosure;

3 is a schematic view showing a structure of a backlight module coated with a photochromic material on a surface of a diffusion sheet, which has improved brightness uniformity, according to some embodiments of the present disclosure;

4 is a schematic structural view of a backlight module coated with a photochromic material on a surface of a reflective sheet according to some embodiments of the present disclosure;

FIG. 5 is a schematic view showing a structure of a backlight module coated with a photochromic material on a surface of a reflective sheet, which has improved brightness uniformity, according to some embodiments of the present disclosure.

Detailed ways

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the embodiments of the present invention have been shown in the drawings, the embodiments Rather, these embodiments are provided so that this disclosure will be more fully understood and the scope of the disclosure will be fully disclosed.

When the inventors applied the prior art, it was found that the prior art improved the brightness uniformity of the light emitted by the backlight module through the V-groove structure, and the improvement effect was poor, and a large amount of debris was often introduced during the V-groove processing. It is easy to cause scratches and white spots.

First, briefly introduce the principle of photochromism:

Photochromism refers to the fact that certain compounds undergo a change in molecular structure under the action of light of a certain wavelength and intensity, resulting in a corresponding change in the peak of light absorption, ie, color, and this change is generally reversible.

Referring to Figure 1, a schematic structural view of an optical film of some embodiments of the present disclosure is shown.

These embodiments of the present disclosure provide an optical film having at least a portion of the position A on the surface of the optical film 11 coated with a transparent photochromic material.

In embodiments of the present disclosure, the photochromic material may be coated on the entire surface of the optical film, or the photochromic material may be applied only locally on the optical film. Alternatively, when a portion of the surface of the optical film is coated with a transparent photochromic material, the coating width d1 of the photochromic material is from 10 mm to 20 mm. The width can effectively shield the bright spots, improve the brightness uniformity of the light passing through the optical film, and save the photochromic material.

The thickness of the photochromic material coating is primarily limited by the total thickness of the optical film. Most optical films currently have a total thickness of less than 300 μm, and therefore, the photochromic material has a coating thickness of less than 200 μm. Alternatively, the thickness of the coating should be less than 100 μm. Without affecting the total thickness of the optical film, the thickness of the coating can be set accordingly according to the actual situation.

Optionally, the photochromic material comprises an organic photochromic material. The organic photochromic materials include spiropyrans, chlorpyrifos, diarylethenes, azobenzenes.

Optionally, the photochromic material comprises an inorganic photochromic material. The inorganic photochromic material includes a transition metal oxide, a metal halide, and a rare earth complex.

Optionally, the photochromic material comprises a transparent resin mixed with a photochromic pigment. When the mixing ratio of the photochromic dye in the transparent resin is larger, the transmittance of light is lower, and the smaller the mixing ratio of the photochromic dye in the transparent resin, the higher the transmittance of light.

The optical film of the embodiments of the present disclosure may be a diffusion sheet, a prism sheet, and a reflection sheet, and a transparent photochromic material may be coated on at least a portion of the surface of any one or more of the optical sheets.

For example, a transparent photochromic material can be applied to at least a portion of the surface of the diffuser. It is also possible to apply a transparent photochromic material at at least a portion of the surface of the prism sheet. It is also possible to apply a transparent photochromic material at at least a portion of the surface of the diffusion sheet and the prism sheet. When the brightness of the light incident on the optical film is uniform, the photochromic material maintains a transparent color. When the brightness of the light incident on the optical film is not uniform, the light intensity value corresponding to the bright spot is large, exceeding the color-changing critical light intensity value of the photochromic material, so that the photochromic material changes from transparent to black. Thereby, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is lowered, and the difference between the brightness at the bright spot and the dark spot is reduced to improve the brightness uniformity of the light passing through the optical film.

The color change critical intensity of a photochromic material is generally related to the performance of the photochromic material and the target brightness of the light.

It should be noted that the photochromic material is coated on at least a part of the surface of the optical film. When the brightness of the light incident on the optical film is not uniform, the light intensity value corresponding to the bright spot is large, and the photochromism is exceeded. The color change critical intensity of the material changes the photochromic material from transparent to black. At this time, the photochromic material at the bright spot does not completely block the light at the place, but the transmittance of the light at the place is reduced, so that the final display brightness at the bright spot is lowered, and the bright spot and the dark spot are reduced. The difference between the brightness increases the brightness uniformity of the light passing through the optical film.

In the embodiment of the present disclosure, by coating a transparent photochromic material on at least a portion of the surface of the optical film, when the brightness of the light incident on the optical film is not uniform, the light intensity at the corresponding bright spot is large. Exceeding the color change critical intensity of the photochromic material causes the photochromic material to change from transparent to black. Therefore, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is lowered, and the difference between the brightness at the bright spot and the dark spot is reduced to improve the brightness uniformity of the light passing through the optical film.

Some embodiments of the present disclosure provide a backlight module including a light source, a light guide plate, and the above optical film. At least a portion of the surface of the optical film is coated with a transparent photochromic material.

Wherein, when a portion of the surface of the optical film is coated with a transparent photochromic material, the photochromic material has a coating width of 10 mm to 20 mm. The photochromic material has a coating thickness of less than 200 μm.

The photochromic material comprises an organic photochromic material. The organic photochromic materials include spiropyrans, chlorpyrifos, diarylethenes, azobenzenes. The photochromic material comprises an inorganic photochromic material. The inorganic photochromic material includes a transition metal oxide, a metal halide, and a rare earth complex.

The photochromic material includes a transparent resin mixed with a photochromic pigment.

In the embodiment of the present disclosure, the photochromic material is coated at a position close to the light source of the backlight module to highlight the bright spot when the light guide plate of the backlight module is adjacent to the light source. Form an occlusion.

The optical film includes one or more of a diffusion sheet, a prism sheet, and a reflection sheet. The light source is an LED light source. The backlight module is a side-entry backlight module.

Referring to FIG. 2, a schematic structural view of a backlight module coated with a photochromic material on a surface of a diffusion sheet is illustrated.

When the optical film is a diffusion sheet of the backlight module, the surface of the diffusion sheet 111 is coated with a transparent photochromic material, and the coating position A1 of the photochromic material is close to the light source 131 of the backlight module. 121 is a combination of a prism sheet, a light guide plate and a reflection sheet in the backlight module, the prism sheet in 121 has the same structure as the prism sheet in the related art, and the reflection sheet in 121 has the same structure as the reflection sheet in the related art.

Referring to FIG. 3, a schematic diagram of a backlight module with a photochromic material coated on a surface of a diffusion sheet, which is improved in brightness uniformity, is shown in some embodiments of the present disclosure.

After the light source 131 is turned on, when the brightness of the light incident on the diffusion sheet 111 is uniform, the photochromic material on the surface of the diffusion sheet 111 maintains a transparent color. When the brightness of the light incident on the diffusion sheet 111 is not uniform, the light intensity value at the bright point is large, exceeding the color-changing critical light intensity value of the photochromic material, so that the photochromic material at the bright point changes from transparent to black, as shown in the figure. A11, A12, A13, A14 and A15 in 3. Thereby, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is lowered, and the difference between the brightness at the bright spot and the dark spot is reduced to improve the brightness uniformity of the light passing through the diffusion sheet.

Referring to FIG. 4, a schematic structural view of a backlight module in which a surface of a reflective sheet is coated with a photochromic material is illustrated in some embodiments of the present disclosure.

When the optical film is a reflective sheet of the backlight module, the surface of the reflective sheet 112 is coated with a transparent photochromic material, and the coating position A2 of the photochromic material is close to the light source 131 of the backlight module. 122 is a combination of a diffusion sheet, a prism sheet, and a light guide plate in the backlight module. The diffusion sheet in 122 has the same structure as the diffusion sheet in the related art, and the prism sheet in 122 has the same structure as the prism sheet in the related art.

Referring to FIG. 5, a schematic diagram of a backlight module with a photochromic material coated on a surface of a reflective sheet, which is improved in brightness uniformity, is shown in some embodiments of the present disclosure.

After the light source 131 is turned on, when the brightness of the light incident on the reflection sheet 112 is uniform, the photochromic material on the surface of the reflection sheet 112 maintains a transparent color. When the brightness of the light incident on the reflection sheet 112 is not uniform, the light intensity value at the bright point is large, exceeding the color-changing critical light intensity value of the photochromic material, so that the photochromic material at the bright point changes from transparent to black, as shown in the figure. A21, A22, A23, A24 and A25 in 5. Thereby, the absorption rate of the light at the bright spot is increased, the reflection of the light is reduced, the bright spot is effectively shielded, and the difference between the brightness at the bright spot and the dark spot is reduced to improve the light passing through the reflective sheet. Brightness uniformity.

Further, it is also possible to apply a photochromic material on the surface of the prism sheet near the light source to improve the brightness uniformity of the light passing through the prism sheet.

According to the principle that the above optical film improves brightness uniformity, the photochromic material can be applied on the upper surface and/or the lower surface of the diffusion sheet at a position close to the light source. It is also possible to apply a photochromic material on the upper surface and/or the lower surface of the prism sheet at a position close to the light source. It is also possible to apply a photochromic material on the upper surface of the reflective sheet at a position close to the light source.

In practical applications, the optical film may include a diffusion sheet, a prism sheet, and a reflection sheet. The number of diffusers can be one or two. When the number of the diffusion sheets is two, according to the distance from the light-emitting surface of the light guide plate, the upper diffusion sheet and the lower diffusion sheet can be divided, and the distance between the upper diffusion sheet and the light-emitting surface of the light guide plate is large, and the lower diffusion sheet and the light guide plate The distance from the exit surface is small. The number of prism sheets may also be one or two. When the number of prism sheets is two, according to the distance from the light-emitting surface of the light guide plate, the upper prism sheet and the lower prism sheet can be divided, and the distance between the upper prism sheet and the light-emitting surface of the light guide plate is large, and the lower prism sheet and the light guide plate are The distance from the exit surface is small.

For example, the photochromic material can be applied to the upper and/or lower surface of the upper diffuser near the source. It is also possible to apply a photochromic material on the upper surface and/or the lower surface of the lower diffusion sheet at a position close to the light source. It is also possible to apply a photochromic material on the upper surface and/or the lower surface of the upper prism sheet at a position close to the light source.

Therefore, according to the actual structure of the backlight module, the photochromic material is coated on the surface of the corresponding optical film near the light source.

Accordingly, embodiments of the present disclosure can also be used to improve Hotspot deficiencies.

The optical film of the embodiments of the present disclosure may be a diffusion sheet, a prism sheet, and a reflection sheet, which are coated by applying a transparent photochromic material on a surface of any one or more of the optical sheets near the light source for improvement. Poor Hotspot. Poor Hotspot refers to the defect that the Hotspot is exposed to the effective light-emitting area of the backlight module to form a light-input side screen.

The diffusion sheet and the prism sheet are located above the light guide plate, that is, on the light exit surface side of the light guide plate. The photochromic material can be applied to the surface of the diffuser near the source. The base color of the diffusion sheet is a transparent color, which uniformly acts on the light emitted from the light guide plate. When no Hotspot defect occurs, the photochromic material maintains a transparent color and has no effect on the display of the screen. When there is a bad occurrence of Hotspot, the light intensity at the bright spot is large, exceeding the critical light intensity value of the photochromic material, so that the photochromic material at the bright spot changes from transparent to black. Thereby, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is reduced, the difference between the brightness at the bright spot and the dark spot is reduced, and the Hotspot defect is effectively improved. It is also possible to apply a photochromic material on the surface of the prism sheet near the light source, which improves the principle of poor Hotspot and is the same as that of the diffusion sheet.

The reflection sheet is located below the light guide plate, that is, on a side facing away from the light exit surface of the light guide plate. The background color of the reflective sheet is transparent, which reflects the light emitted from the light guide plate and improves the utilization of light. When no Hotspot defect occurs, the photochromic material maintains a transparent color and has no effect on the display of the screen. When there is a bad occurrence of Hotspot, the light intensity at the bright spot is large, exceeding the critical light intensity value of the photochromic material, so that the photochromic material at the bright spot changes from transparent to black. Thereby, the absorption rate of the light at the bright spot is increased, the reflection of the light is reduced, the bright spot is effectively shielded, and the difference between the brightness at the bright spot and the dark spot is reduced, thereby effectively improving the Hotspot defect. For a detailed description of the optical film, reference may be made to the description of the prior embodiment, which is not described in detail in this embodiment.

Of course, the backlight module may further include a backlight module assembly such as a plastic frame and a front frame, which is similar to the conventional backlight module assembly, and is not described herein.

In the embodiment of the present disclosure, the backlight module includes a light source, a light guide plate, and an optical film. By coating a transparent photochromic material at at least a portion of the surface of the optical film, when the brightness of the light incident on the optical film is not uniform, the light intensity at the corresponding bright spot is large, exceeding the photochromic material. The color change critical intensity value causes the photochromic material to change from transparent to black. Thereby, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is reduced, and the difference between the brightness at the bright spot and the dark spot is reduced, so as to improve the brightness uniformity of the light passing through the optical film, and also Improve the brightness uniformity of the light emitted by the backlight module.

Some embodiments of the present disclosure provide a display device, including the backlight module, the backlight module includes a light source, a light guide plate, and an optical film, and at least a portion of the surface of the optical film is coated with a transparent surface. Photochromic material.

The photochromic material is disposed adjacent to the light source of the backlight module to form a occlusion of the bright spot when a bright spot appears on a light guide plate of the backlight module near the light source.

The optical film includes one or more of a diffusion sheet, a prism sheet, and a reflection sheet. The light source is an LED light source.

For a detailed description of the backlight module, reference may be made to the description of the prior embodiment, which is not described in this embodiment.

The display device may be any product or component having a display function, such as a mobile phone, a tablet computer, a television, a display, a notebook computer, a navigator, and the like.

Since the display device of the present embodiment includes the backlight module in the prior embodiment, the display effect is better.

In the embodiment of the present disclosure, the display device includes a backlight module, and the backlight module includes a light source, a light guide plate, and an optical film. By coating a transparent photochromic material at at least a portion of the surface of the optical film, when the brightness of the light incident on the optical film is not uniform, the light intensity at the corresponding bright spot is large, exceeding the photochromic material. The color change critical intensity value causes the photochromic material to change from transparent to black. Thereby, the bright spot can be effectively shielded, so that the light transmittance at the bright spot is lowered, and the difference between the brightness at the bright spot and the dark spot is reduced to improve the brightness uniformity of the display device.

The above is a detailed description of the optional embodiments of the present disclosure, but the present disclosure is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present disclosure within the scope of the technical idea of the present disclosure. Variations are all within the scope of protection of the present disclosure. It should be further noted that the specific technical features described in the above specific embodiments may be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure is applicable to various possibilities. The combination method will not be described separately. In addition, any combination of various embodiments of the present disclosure may be made as long as it does not deviate from the idea of the present disclosure, and should also be regarded as the disclosure of the present disclosure.

The various embodiments in the present specification are described in a progressive manner, and each embodiment focuses on differences from other embodiments, and the same similar parts between the various embodiments can be referred to each other.

In addition, those skilled in the art will appreciate that, although some embodiments described herein include certain features that are included in other embodiments and not in other features, combinations of features of different embodiments are intended to be within the scope of the present disclosure. Different embodiments are formed and formed. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

Although alternative embodiments of the embodiments of the present application have been described, those skilled in the art can make additional changes and modifications to the embodiments once they are aware of the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all alternatives and modifications of the embodiments.

Finally, it should also be noted that in this context, relational terms such as first and second are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply these entities. There is any such actual relationship or order between operations. Furthermore, the terms "comprises" or "comprising" or "comprising" or any other variations are intended to encompass a non-exclusive inclusion, such that a process, method, item, Other elements, or elements that are inherent to such a process, method, commodity, or equipment. An element defined by the phrase "comprising a ..." does not exclude the presence of additional equivalent elements in the process, method, item, or device including the element.

The optical film, the backlight module and the display device provided by the present disclosure have been described in detail above. The principles and embodiments of the present disclosure have been described herein with reference to specific examples, and the description of the above embodiments is only to assist in understanding the method of the present disclosure and its core idea. In the meantime, the present invention is not limited by the scope of the present disclosure.

Claims

An optical film, wherein at least a portion of a surface of the optical film is coated with a transparent photochromic material.
The optical film of claim 1, wherein the photochromic material has a coating width of 10 mm to 20 mm when a portion of the surface of the optical film is coated with a transparent photochromic material. .
The optical film of claim 1, wherein the photochromic material has a coating thickness of less than 200 μm.
The optical film of claim 1 wherein the photochromic material comprises an organic photochromic material.
The optical film of claim 4, wherein the organic photochromic material comprises spiropyrans, chlorpyrifos, diarylethenes, azobenzenes.
The optical film of claim 1 wherein the photochromic material comprises an inorganic photochromic material.
The optical film of claim 6, wherein the inorganic photochromic material comprises a transition metal oxide, a metal halide, a rare earth complex.
The optical film according to any one of claims 1 to 7, wherein the photochromic material comprises a transparent resin mixed with a photochromic dye.
A backlight module comprising a light source, a light guide plate and the optical film according to any one of claims 1 to 8.
The backlight module of claim 9, wherein the photochromic material is disposed adjacent to the light source of the backlight module to appear near the light source on the light guide plate of the backlight module. The highlight is occluded when the highlight is highlighted.
The backlight module of claim 9, wherein the optical film comprises one or more of a diffusion sheet, a prism sheet, and a reflection sheet.
The backlight module according to any one of claims 9 to 11, wherein the light source is an LED light source.
A display device comprising the backlight module according to any one of claims 9 to 12.